Most temperature controls designed for home baths are operated manually, that is, the user must adjust the hot and cold water proportions by feel until an ideal temperature is reached. Because it is difficult to make precise adjustments with manual units, and because the body is sensitive to small differences in temperature, considerble time and water may be wasted in acquiring the most comfortable water temperature. In addition, as the supply water temperature is affected by the heat sink effect of plumbing pipes and fixtures through which it runs, and generally the user must make adjustments to compensate for this effect. Finally, as the hot water supply approaches depletion, the supply temperature begins dropping off so quickly that many times a constant, comfortable temperature of water is impossible to sustain by manual adjustment.
There is a need, therefore, for a convenient mixing device that quickly and efficiently performs precise adjustments to achieve and maintain a constant temperature output and on a preprogrammed basis.